Linux Certif

Toute la documentation sur la certification Linux LPI

JavaScript::Context.3pm

NAME

JavaScript::Context - An object in which we can execute JavaScript

SYNOPSIS

   use JavaScript;
 
   # Create a runtime and a context
   my $rt = JavaScript::Runtime->new();
   my $cx = $rt->create_context();
 
   # Add a function which we can call from JavaScript
   $cx->bind_function(print => sub { print @_; });
 
   my $result = $cx->eval($source);
 
 

INTERFACE

INSTANCE METHODS

bind_class ( %args )

Defines a new class that can be used from JavaScript in the contet.

It expects the following arguments

name

The name of the class in JavaScript.

   name => "MyPackage",
 
 

constructor

A reference to a subroutine that returns the Perl object that represents the JavaScript object. If omitted a default constructor will be supplied that calls the method "new" on the defined package (or name if no package is defined).

   constructor => sub { MyPackage->new(@_); },
 
 

package

The name of the Perl package that represents this class. It will be passed as first argument to any class methods and also used in the default constructor.

   package => "My::Package",
 
 

methods (fs)

A hash reference of methods that we define for instances of the class. In JavaScript this would be "o = new MyClass(); o.method()".

The key is used as the name of the function and the value should be either a reference to a subroutine or the name of the Perl subroutine to call.

   methods => { to_string => \&My::Package::to_string,
                random    => "randomize"
   }
 
 

static_methods (static_ps)

Like fs but these are called on the class itself. In JavaScript this would be "MyClass.method()".

properties (ps)

A hash reference of properties that we define for instances of the class. In JavaScript this would be "o = new MyClass(); f = o.property;"

The key is used as the name of the property and the value is used to specify what method to call as a get-operation and as a set-operation. These can either be specified using references to subroutines or name of subroutines. If the getter is undefined the property will be write-only and if the setter is undefined the property will be read-only. You can specify the getter/setter using either an array reference, "[\&MyClass::get_property, \&MyClass::set_property]", a string, "MyClass::set_property MyClass::get_property" or a hash reference, "{ getter =" ``MyClass::get_property'', setter => ``MyClass::set_property'' }>.

   ps => { length => [qw(get_length)],
           parent => { getter => \&MyClass::get_parent, setter => \&MyClass::set_parent },
         }
 
 

static_properties (static_ps)

Like ps but these are defined on the class itself. In JavaScript this would be "f = MyClass.property".

flags

A bitmask of attributes for the class. Valid attributes are:

JS_CLASS_NO_INSTANCE

Makes the class throw an exception if JavaScript tries to instansiate the class.

bind_function ( name => $name, func => $subroutine )

bind_function ( $name => $subroutine )

Defines a Perl subroutine ($subroutine_ref) as a native function with the given $name. The argument $subroutine can either be the name of a subroutine or a reference to one.

bind_object ( $name => $object )

Binds a Perl object to the context under a given name.

bind_value ( $name => $value )

Defines a value with a given name and value. Trying to redefine an already existing property throws an exception.

unbind_value ( $name )

Removed a property from the context or a specified object.

call ( $name, @arguments )

call ( $function, @arguments )

Calls a function with the given name $name or the JavaScript::Function-object $function and passes the rest of the arguments to the JavaScript function.

can ( $name )

Returns true if there is a function with a given $name, otherwise it returns false.

compile ( $source )

Pre-compiles the JavaScript given in $source and returns a "JavaScript::Script"-object that can be executed over and over again. If an error occures because of a compilation error it returns undef and $@ is set.

eval ( $source )

Evaluates the JavaScript code given in $source and returns the result from the last statement.

If there is a compilation error (such as a syntax error) or an uncaught exception is thrown in JavaScript this method returns undef and $@ is set.

eval_file ( $path )

Evaluates the JavaScript code in the file specified by $path and returns the result from the last statement.

If there is a compilation error (such as a syntax error) or an uncaught exception is thrown in JavaScript this method returns undef and $@ is set.

find ( $native_context )

Returns the "JavaScript::Context"-object associated with a given native context.

set_branch_handler ( $handler )

Attaches an branch callback handler (a function that is called when a branch is performed) to the context. The argument $handler may be a code-reference or the name of a subroutine.

To remove the handler call this method with an undefined argument.

The handler is called when a script branches backwards during execution, when a function returns and the end of the script. To continue execution the handler must return a true value. To abort execution either throw an exception or return a false value.